The map below shows the 20 metropolitan areas that lost the greatest share of local people to other parts of the country between July 2013 and July 2014, according to a Bloomberg News analysis of U.S. Census Bureau data. The New York City area ranked 2nd, losing about a net 163,000 U.S. residents, closely followed by a couple surrounding suburbs in Connecticut. Honolulu ranked fourth and Los Angeles ranked 14th. The Bloomberg calculations looked at the 100 most populous U.S. metropolitan areas.

Interestingly, these are also the cities with some of the highest net inflows of people from outside the country. That gives many of these cities a steadily growing population, despite the net exodus of people moving within the U.S.

So what's going on here? Michael Stoll, a professor of public policy and urban planning at the University of California Los Angeles, has an idea. Soaring home prices are pushing local residents out and scaring away potential new ones from other parts of the country, he said. (Everyone knows how unaffordable the Manhattan area has become.)